Place chicken on grill and season generously with salt. When browned, turn chicken and salt second side.
Meanwhile, make Campari sauce: In a medium saucepan, bring Campari to a boil and let it reduce by half. Turn flame down and add sugar, pepper and cream. Reduce a little more if needed until it thickens a little.
Transfer a little sauce to a small bowl, brush on tops of chicken and flip to sear. To serve: Place chicken on platter and pass more sauce. Serves 4.